Contact probe and method of making the same

ABSTRACT

To provide a contact probe which can easily be connected with a measurement apparatus electrically, can measure a high speed and high frequency signal with a fine pitch easily and correctly, and can easily cope with signal measurement for a plurality of channels, and a method of making the contact probe. 
     It includes a first printed wiring board  3  having a signal electrode  10   a  and a ground electrode  10   b  used as a contact part with respect to a measuring object, in which the signal electrode  10   a  and ground electrode  10   b  are formed of a metal wiring pattern on a substrate, and a second printed wiring board  2  with a coaxial line structure having shield electrodes  12, 17, 18  which enclose a signal line  15   a  and the surroundings of the signal line  15   a  through an insulating layer. The signal electrode  10   a  of the first printed wiring board  3  and the signal line  15   a  of the second printed wiring board  2  are electrically connected together, and the ground electrode  10   b  of the first printed wiring board  3  and the shield electrodes  12, 17, 18  of the second printed wiring board  2  are electrically connected together.

This application is a 371 of PCT/JP2007/058561 filed on Apr. 19, 2007.

TECHNICAL FIELD

The present invention relates to a contact probe and a method of makingthe same which are used for measuring a high frequency characteristic ofa semiconductor integrated circuit, a package for a semiconductorintegrated circuit, a printed circuit board, etc., especially correspondto a plurality of channel signals.

BACKGROUND ART

Recently, as an electric apparatus has been faster and of a higherfrequency, there has been an increasing need, compared with conventionalones, to measure and inspect electrical characteristics with respect toa high speed and a high frequency signal of an electronic device, anelectronic component, a mounting component, etc. which constitute anapparatus. A high frequency contact probe is used in the case of suchmeasurement and inspection. The conventional high frequency contactprobe is predominantly arranged such that a fine metal contact pad isconnected to a tip of a thin-line rigid coaxial cable. As a product, thehigh frequency contact probes from GGB Industries, Inc., CascadeMicrotech, Inc., and Suss MicroTec are widely used, for example.

However, there is a problem in that as for many of the contact probesused conventionally and widely, even a fine electrode pitch at the tip(interval between signal electrode and ground electrode) isapproximately 100 μm, then it is difficult to evaluate characteristicsof an interposer etc. for an integrated circuit having a fine pitch ofless than 50 μm.

As a technology which solves such a problem, patent document 1 disclosesa probe tip component which has the signal electrode and groundelectrode brought into contact with a measuring object and is made froma printed circuit board, and the above-mentioned probe tip component iselectrically connected to the tip of a coaxial cable by soldering.

According to the structure as disclosed in patent document 1, theelectrode pitch of the probe tip component can be arranged to be lessthan 50 μm by way of a technology of manufacturing the printed wiringboard, and even the measuring object with a fine pitch allows the highspeed and the high frequency signal to be measured.

Patent document 1: Japanese Patent Application Publication (KOKAI) No.2006-10678

DISCLOSURE OF THE INVENTION Object of the Invention

However, in the contact probe as disclosed by patent document 1, thereis a problem in that when connecting the coaxial cable, which is from ameasurement apparatus, to the probe tip component directly, it isdifficult to perform the connection exactly by soldering, since theprobe tip component is very small.

Further, in the case where there are a plurality of measuring objects,if the pitch between the respective measuring objects is large, it ispossible to measure it by means of a plurality of single-channelhigh-frequency probes as shown in patent document 1. However, in thecase where the pitch between the respective measuring objects is small,use of the high frequency contact probes corresponding to a plurality ofchannel signals for a plurality of channels is indispensable.

However, in the case where the high frequency probe corresponding to aplurality of channels is constituted by the conventional single-channelhigh-frequency contact probes including the probes as disclosed inpatent document 1, it is necessary to arrange a plurality of probe tipsin a horizontal line, for example, and it is technically difficult toarrange a plurality of probes at a fine pitch of 50 μm or less.

The present invention arises in a situation as described above, and aimsat providing a contact probe which can easily be connected with ameasurement apparatus electrically, can measure a high speed and highfrequency signal with a fine pitch easily and correctly, and can copewith signal measurement for a plurality of channels, and a method ofmaking the contact probe.

Means to Solve the Problem

The contact probe in accordance with the present invention made in orderto solve the above-mentioned problem is a contact probe used formeasuring and evaluating the high speed and high frequencycharacteristic, the contact probe including a first printed wiring boardhaving a signal electrode and a ground electrode used as a contact partwith respect to a measuring object, in which the signal electrode andground electrode are formed of a metal wiring pattern on a substrate,and a second printed wiring board with a coaxial line structure having ashield electrode which encloses a signal line and the surroundings ofthe signal line through an insulating layer, characterized in that thesignal electrode of the above-mentioned first printed wiring board andthe signal line of the above-mentioned second printed wiring board areelectrically connected together, and the ground electrode of theabove-mentioned first printed wiring board and the shield electrode ofthe above-mentioned second printed wiring board are electricallyconnected together. In addition, it is desirable that the electrodepitch between the above-mentioned signal electrode and theabove-mentioned ground electrode is arranged to be equal to or greaterthan 10 μm or less than 50 μm.

By making the contact probe from the printed wiring board in this way,the probe tip part (first printed wiring board) having a fine (forexample, less than 50 μm) electrode pitch can be easily formed withsufficient accuracy. Therefore, the probe tip can be pressed againstfine pitch portions formed at a semiconductor integrated circuit, apackage for the semiconductor integrated circuit, the printed circuitboard, etc., and the high speed and high frequency measurement can berealized.

Further, since electrical connection between the first printed circuitboard (probe tip part) and the measurement apparatus (coaxial cable) isachieved through the second printed circuit board which has a coaxialline structure, the connection can be performed easily and correctly. Inparticular, since the connection between the first printed circuit boardto have a fine structure and the second printed circuit board isconnection between the substrates, it can be performed through finebumps etc. and it is possible to achieve easy and exact electricconnection.

Further, since the second printed circuit board has the coaxial linestructure, it is possible to improve transmission efficiency of the highspeed and high frequency signal, and to reduce an incoming noise and across talk occurred between wirings.

Furthermore, since the first printed circuit board whose tip part is ofa very fine structure and the second printed circuit board areelectrically connected together through the fine bumps, it is possibleto reduce a deviation of the characteristic impedance at the connectionpart and to improve the transmission characteristic greatly.

In addition, although it is possible to make the first printed circuitboard and the second printed circuit board integrally on one printedcircuit board, it is necessary to use “via connection” structure in thatcase. However, since the conventional “via connection” structureprovides an insufficient high frequency characteristic, the presentinvention employs fine bump connection.

Further, in the above-mentioned second printed wiring board, it isdesirable to form the ground line which is electrically connected to theabove-mentioned shield electrode in the same plane as theabove-mentioned signal line, and to form a cut-off portion so that apredetermined area of either upper or lower sides of the above-mentionedsignal line and the above-mentioned ground line may be exposed.

In the second printed wiring board, by forming the cut-off portion inthis way, the connection part connecting with the first printed wiringboard is provided, and the connection can be achieved easily.

Further, it is desirable that a plurality of groups of signal electrodesand ground electrodes are formed in the above-mentioned first printedwiring board, corresponding groups of signal lines and shield electrodesare formed in the above-mentioned second printed wiring board, thesignal electrodes of the above-mentioned first printed wiring board andthe signal lines of the above-mentioned second printed wiring board areelectrically connected together for each corresponding group, and theground electrodes of the above-mentioned first printed wiring board andthe shield electrodes of the above-mentioned second printed wiring boardare electrically connected together for each corresponding group.

Thus, by forming a plurality of channels (plurality of groups) ofelectrodes by means of the printed wiring boards, it is possible to formand arrange the plurality of electrodes at the contact probe tip, inwhich the electrode pitch is fine (for example, less than 50 μm).Therefore, even in the case where the plurality of channels of measuringobjects are located at a fine pitch, it is possible to measure the highspeed and high frequency signal for each channel by the contact probecoping with the plurality of channels.

Further, by forming a shape of the second printed wiring board into theshape of a fan where a width of a rear end (connection side with coaxialcable) is gradually extended, it is possible to widen the pitch betweenthe electrodes of adjoining channels at the rear end, and to easilyachieve the connection with the coaxial cable which is from themeasurement apparatus.

Further, the method of making the contact probe in accordance with thepresent invention made in order to solve the above-mentioned subject isa method of making a contact probe used for measuring and evaluating ahigh speed and high frequency characteristic, characterized byimplementing a step of making a first printed wiring board in which asignal electrode and a ground electrode used as a contact part withrespect to a measuring object are formed of a metal wiring pattern, andmaking a second printed wiring board with a coaxial line structurehaving a shield electrode which encloses a signal line and thesurroundings of the above-mentioned signal line through an insulatinglayer, and a step of electrically connecting the signal line of theabove-mentioned second multilayer printed wiring board to the signalelectrode of the above-mentioned first printed wiring board, andelectrically connecting the shield electrode of the above-mentionedsecond printed wiring board to the ground electrode of theabove-mentioned first printed wiring board.

By way of such a method, it is possible to make the contact probe formedof the printed wiring board, and the probe tip of this contact probe canbe pressed against the fine pitch portions formed at the semiconductorintegrated circuit, the package for the semiconductor integratedcircuit, the printed circuit board, etc., to realize the high speed andhigh frequency measurement.

Further, it is desirable that the plurality of groups of signalelectrodes and ground electrodes are formed in the above-mentioned firstprinted wiring board, corresponding groups of signal lines and shieldelectrodes are formed in the above-mentioned second printed wiringboard, the signal electrodes of the above-mentioned first printed wiringboard and the signal lines of the above-mentioned second printed wiringboard are electrically connected together for each corresponding group,and the ground electrodes of the above-mentioned first printed wiringboard and the shield electrodes of the above-mentioned second printedwiring board are electrically connected together for each correspondinggroup.

In the case of the plurality of measuring objects, even if the pitchbetween the respective measuring objects is fine (for example, less than50 μm), it is possible to make the corresponding plurality of channels(plurality groups) of contact probes, and to measure the high speed andhigh frequency signal for each channel by way of such a method.

In addition, the process of making the first printed wiring board andthe second printed wiring board may employ a production method similarto a process of making a so-called silicon interposer. In this case,precision of fine line pattern forming is improved, and controllabilityof characteristic impedance of the lines is improved, to thereby improvethe transmission characteristic.

Furthermore, in the step of making the above-mentioned first printedwiring board, it is desirable to perform a step of laminating athin-film metal layer on a substrate made of silicon or glass, a step oflaminating an insulating layer on the above-mentioned metal layer, astep of forming a photoresist pattern for forming the signal electrodeand the ground electrode on the above-mentioned insulating layer, a stepof laminating a metal layer on the insulating layer on which theabove-mentioned photoresist pattern is formed, and a step of removingthe above-mentioned photoresist pattern and forming the signal electrodeand the ground electrode by the metal layer laminated on theabove-mentioned insulating layer.

In addition, in the step of making the above-mentioned first printedwiring board, it is possible to perform a step of laminating a thin-filmmetal layer on a substrate made of silicon or glass, a step oflaminating an insulating layer on the above-mentioned metal layer, astep of laminating a metal layer on the above-mentioned insulatinglayer, and a step of forming a metal wiring pattern to be the signalelectrode and the ground electrode on an uppermost metal layer byetching.

Alternatively, in the step of making the above-mentioned first printedwiring board, it is possible to perform a step of forming, by etching, ametal wiring pattern to be the signal electrode and the ground electrodeon the metal layer of either upper or lower side of the insulating layerwhose both sides are joined with thin-film metal layers.

By performing such a step, it is possible to form a probe tip part(first printed wiring board) whose electrode pitch is fine (for example,less than 50 μm) easily and with sufficient accuracy.

Further, in the step of making the above-mentioned second printed wiringboard, it is desirable to perform a step of laminating an insulated sideof an insulating layer whose one side is joined with a metal layer, ontoa metal layer of either upper or lower side of an insulating layer whoseboth sides are joined with a thin-film metal layer, a step of forming ametal wiring pattern to be the signal line and the ground line at anuppermost metal layer by etching, a step of laminating an insulatingside of the insulating layer whose one side is joined with a metallayer, onto a side where the above-mentioned metal wiring pattern isformed, a step of carrying out a grooving process, respectively on bothsides of the above-mentioned signal line along an extended direction ofthe above-mentioned signal line, towards a lower part from an upperpart, intersecting the above-mentioned ground line, and reaching a metallayer lower than the above-mentioned signal line, a step of subjecting,at least, a portion subjected to the above-mentioned grooving process toa metal plating process to form the shield electrode which encloses thesurroundings of the above-mentioned signal line through the insulatinglayer, and a step of performing a cutting process so that apredetermined area of either upper or lower sides of the above-mentionedsignal line and ground line may be exposed respectively.

By performing such a step, it is possible to make the second circuitboard having the coaxial line structure. Further, connection between thefirst printed wiring board and the coaxial cable from measurementapparatus is carried out through this second printed wiring board, andthe connection with each of them is easily carried out.

In addition, it is desirable to use a prepreg including any of polyimideresin, BCB resin, polyamide resin, polyoxazole resin, epoxy resin,Teflon (registered trademark) resin, and cycloolefin resin for each ofthe above-mentioned insulating layers.

Further, it is desirable that the metal layer laminated to theabove-mentioned insulating layer is formed of either gold, silver, orcopper.

Furthermore, it is desirable that the metal plating carried out for theportion subjected to the above-mentioned grooving process is copperplating.

According to the present invention, the contact probe is provided whichcan easily be connected with the measurement apparatus electrically, canmeasure the high speed and high frequency signal with the fine pitcheasily and correctly, and can cope with signal measurement for theplurality of channels, and the method of making the contact probe isprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing a first preferred embodiment of a contactprobe in accordance with the present invention.

FIG. 2 is a bottom view of the contact probe in FIG. 1.

FIG. 3 is a perspective view from above of a probe main body and a probetip part of the contact probe in FIG. 1.

FIG. 4 is a perspective view from below of the probe main body and theprobe tip part of the contact probe in FIG. 1.

FIG. 5 is a flowchart showing a method of making the probe main body.

FIG. 6A is a sectional view illustrating a flow step corresponding tothe flowchart in FIG. 5.

FIG. 6B is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6A.

FIG. 6C is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6B.

FIG. 6D is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6C.

FIG. 6E is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6D.

FIG. 6F is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6E.

FIG. 6G is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6F.

FIG. 6H is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 5 subsequent to FIG. 6G.

FIG. 7 is a flowchart showing a method of making the probe tip part.

FIG. 8A is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 7.

FIG. 8B is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 7 subsequent to FIG. 8A.

FIG. 8C is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 7 subsequent to FIG. 8B.

FIG. 8D is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 7 subsequent to FIG. 8C.

FIG. 8E is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 7 subsequent to FIG. 8D.

FIG. 9 is a flowchart showing another method of making the probe tippart.

FIG. 10A is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9.

FIG. 10B is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9 subsequent to FIG. 10A.

FIG. 10C is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9 subsequent to FIG. 10B.

FIG. 10D is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9 subsequent to FIG. 10C.

FIG. 10E is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9 subsequent to FIG. 10D.

FIG. 10F is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 9 subsequent to FIG. 10E.

FIG. 11 is a flowchart showing another method of making the probe tippart.

FIG. 12A is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 11.

FIG. 12B is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 11 subsequent to FIG. 12A.

FIG. 12C is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 11 subsequent to FIG. 12B.

FIG. 12D is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 11 subsequent to FIG. 12C.

FIG. 13 is a flowchart showing a method of making contact bumps of theprobe tip part.

FIG. 14A is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 13.

FIG. 14B is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 13 subsequent to FIG. 14A.

FIG. 14C is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 13 subsequent to FIG. 14B.

FIG. 14D is a sectional view illustrating the flow step corresponding tothe flowchart in FIG. 13 subsequent to FIG. 14C.

FIG. 15 is a plan view showing a second preferred embodiment of thecontact probe in accordance with the present invention.

FIG. 16A is a plan view showing a structure of the probe main body ofthe contact probe of FIG. 15.

FIG. 16B is a sectional view along arrows A-A in FIG. 16A.

FIG. 17A is a plan view showing a structure of the probe tip part of thecontact probe in FIG. 15.

FIG. 17B is a sectional view along arrows B-B in FIG. 17A.

FIG. 18A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming a cut-off portion.

FIG. 18B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 19A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 19B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 20A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 20B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 21A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 21B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 22A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 22B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 23A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 23B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 24A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 24B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 25A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 25B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 26A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 26B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 27A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 27B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 28A is a sectional view (front view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 28B is a sectional view (side view) illustrating a flow step, forexplaining another method of forming the cut-off portion.

FIG. 29 is a flowchart for explaining another method of forming thecut-off portion.

FIG. 30A is a view for explaining a method of connecting a coaxial cableto a coaxial line formed in the substrate.

FIG. 30B is a view for explaining a method of connecting the coaxialcable to the coaxial line formed in the substrate.

FIG. 30C is a view for explaining a method of connecting the coaxialcable to the coaxial line formed in the substrate.

FIG. 31A is a view for explaining a method of connecting the coaxialcable to the coaxial line formed in the substrate.

FIG. 31B is a view for explaining a method of connecting the coaxialcable to the coaxial line formed in the substrate.

FIG. 31C is a view for explaining a method of connecting the coaxialcable to the coaxial line formed in the substrate.

DESCRIPTION OF REFERENCE SIGNS

-   2: probe main body (second printed wiring board)-   2 a: cut-off portion-   3: probe tip part (first printed wiring board)-   4: fine bumps-   5: substrate-   6: reinforcing board-   7: contact bumps-   8: insulating layer-   9: metal layer-   10: metal layer-   10 a: signal electrode-   10 b: ground electrode-   11: insulating layer-   12: metal layer-   13: metal layer-   14: insulating layer-   15: metal layer-   15 a: signal line-   15 b: ground line-   16: insulating layer-   17: metal layer-   18: metal plated layer-   19: groove portion-   20: probe main body (second printed wiring board)-   30: probe tip part (first printed wiring board)-   100: contact probe-   101: contact probe

BEST MODE FOR IMPLEMENTING THE INVENTION

Hereafter, the preferred embodiments of a contact probe and a method ofmaking the same in accordance with the present invention will bedescribed with reference to the drawings. FIG. 1 is a side view showinga first preferred embodiment of a contact probe in accordance with thepresent invention. FIG. 2 is a bottom view of the contact probe inFIG. 1. In addition, the contact probe as shown in the first preferredembodiment is a probe with a structure corresponding to a single channel(single group).

As illustrated, a contact probe 100 has a probe tip part 3 used as acontact part coming into contact with a measuring object, and a probemain body 2 connected with a high frequency measurement apparatusthrough a coaxial cable etc. (not shown).

The probe tip part 3 (first printed wiring board) and the probe mainbody 2 (second printed wiring board) are respectively formed fromprinted wiring boards, which are mutually joined by thermocompression at100° C. through 150° C. using fine bumps 4. In addition, it ispreferable that the fine bumps 4 are formed of either gold, a goldalloy, silver, or a silver alloy.

Further, although the fine bumps are used, electric connection betweenthe probe tip part 3 and the probe main body 2 may be carried out bypressure contact, without forming a junction by way ofthermocompression. In this case, after applying thermosetting resin intoa gap between the probe tip part 3 and the probe main body 2, they arebrought into pressure contact with each other, and the hardening andshrinking by heating raises the contact pressure, thus being possible tosecure the electric connection. Such a method is referred to as the NCP(Non Conductive Paste) process.

Further, since there is a possibility that the junction by means of thefine bumps 4 provides by itself insufficient strength as the probe, thesubstrate 5 made of silicon or glass is formed on the upper layer of theprobe main body 2 as shown in FIG. 1, whereby the reinforcing board 6made from a resin board, a metal plate, etc. is adhered to, withadhesives, upper surfaces of the probe main body 2 and the probe tippart 3 which are flattened.

In addition, in the case where the substrate 5 is formed of glass,transparency is acquired in the probe tip part 3 and visibility withrespect to an electrode position is improved, thus positioning is easywhen in contact with the measuring object. If this is the case, it isdesirable that the reinforcing board is also formed of transparent resinetc.

Further, as described above, in the case where the electric connectionbetween the probe tip part 3 and the probe main body 2 is realized byway of pressure contact, if the adhesive of the reinforcing board 6 andthe resin sealed in the gap between the probe tip part 3 and the probemain body 2 are dissolved by a solvent, an acid, etc. as a remover thenthe probe tip part 3 can be replaced.

Further, as shown in FIG. 2, three lines (one signal electrode 10 a andtwo ground electrodes 10 b) are formed at a metal wiring pattern 10beneath the probe tip part 3, and contact bumps 7 (one signal contactbump 7 a and two grounding contact bumps 7 b) for contacting themeasuring object are formed at respective tips. That is, the signalcontact bump 7 a provided for the tip of central signal electrode 10 ais a contact bump for picking up a signal from the measuring object.Further, the grounding contact bumps 7 b provided for the tips of groundelectrodes 10 b on both sides are contact bumps for picking up a groundlevel signal on the measuring object side. In addition, the electrodepitch of the signal contact bump 7 a and the grounding contact bumps 7 bis set as 10 to 50 μm, for example.

Further, in the probe main body 2, the coaxial cable (not shown) may beconnected with an opposite side (rear end side) of a side to which theprobe tip part 3 is connected. By connecting the coaxial cable to thehigh frequency measurement apparatus etc., it is possible to measure ahigh frequency signal. In other words, according to this contact probe100, since the probe tip part 3 is made from the printed wiring board, adesired electrode pitch of less than 50 μm (for example) can be formedeasily, and it is possible to measure the fine pitch of the measuringobject. Further, the probe main body 2 has the coaxial line structure aswill be described in detail later, to thereby improve transmissionefficiency of the high speed and high frequency signal, and to reduce anincoming noise and a cross talk occurred between wirings. In addition, alength in an extended direction of the coaxial line of the probe mainbody 2 is formed and set up arbitrarily.

Further, since the probe main body 2 is made from the printed wiringboard having the coaxial line structure as described above, it ispossible to facilitate the connection with the probe tip part 3, and theconnection with the coaxial cable from the measurement apparatusrespectively. In other words, the electric connection between the probetip part 3 and the measurement apparatus can be achieved easily andcorrectly. Especially, since the connection between the probe tip part 3to have a fine structure and the probe main body 2 is the connectionbetween the substrates, it can be performed through the fine bumps 4 andit is possible to realize easy and exact electric connection.

Then, the structures of the probe main body 2 and the probe tip part 3will be described in more detail. FIG. 3 is a perspective view fromabove of the probe main body 2 and the probe tip part 3. FIG. 4 is aperspective view from below.

Firstly, the structure of the probe main body 2 will be described. Asshown in FIG. 3, the probe main body 2 is a printed wiring board made tobe of a multilayer structure where an insulating layer 11, a metal layer12, an insulating layer 14, a metal layer 15, an insulating layer 16, ametal layer 17, and a metal plated layer 18 are laminated in order on aground layer 13 that is the lowermost layer. Among these, the metallayer 15 is constituted by a signal line 15 a and ground lines 15 bformed on both sides through the insulating layer 14. In other words, itis arranged that the signal line 15 a is electrically insulated from theground lines 15 b.

Further, as shown in FIG. 3, along the extended direction of the signalline 15 a and ground lines 15 b, (two) groove portions 19 are formed onboth sides of the signal line 15 a from the upper surface of the probemain body 2 towards the lower part, and the metal plated layer 18 isformed also on surfaces of the groove portions 19. Here, the grooveportions 19 intersect the ground lines 15 b and are formed to have adepth to the extent of reaching the metal layer 12, so that the metalplated layer 18 allows the metal layer 12, the ground lines 15 b, andthe metal layer 17 to be electrically connected to one another. In otherwords, the coaxial line structure is provided where the shieldelectrodes which surround the signal line 15 a through the insulatinglayer are formed.

Further, as shown in FIG. 3, at an upper tip of the probe main body 2,the upper surfaces of the signal line 15 a and the ground lines 15 b areexposed, and a cut-off portion 2 a is provided to form a connection partconnecting with the probe tip part 3.

Next, the structure of the probe tip part 3 will be described. As shownin FIG. 3 and FIG. 4, the probe tip part 3 is arranged to have astructure where a metal layer 9 is formed at an upper layer of aninsulating layer 8, and a metal layer 10 is formed at a lower layer. Asfor the metal layer 10, as described above, the signal electrode 10 a isformed in the center, and the ground electrodes 10 b are formed on boththe sides.

In the case where this probe tip part 3 is connected to the probe mainbody 2, it is arranged that the above-mentioned fine bumps 4electrically connect a rear end 10 c (see FIG. 4) of the signalelectrode 10 a with the upper surface (see FIG. 3) of signal line 15 aat the cut-off portion 2 a, and rear ends 10 d (see FIG. 4) of theground electrodes 10 b with the upper surfaces (see FIG. 3) of groundlines 15 b at the cut-off portion 2 a.

In addition, it is arranged that a tip part 10 e of the signal electrode10 a as shown in FIG. 4 and tip parts 10 f of the ground electrodes 10 bare respectively provided with the contact bumps 7 a and 7 b as shown inFIG. 2.

Then, a method of making the probe main body 2 and the probe tip part 3will be described. At first, according to the flowchart in FIG. 5 andthe illustrated flow steps in FIG. 6A through FIG. 6H corresponding tothe flowchart, the method of making the probe main body 2 having thecoaxial line structure will be described.

Firstly, as shown in FIG. 6A, a double-side metal-coated resin coresubstrate in which the thin-film metal layers 12 and 13 are respectivelylaminated to both sides of the insulating layer 11 is prepared (step S1in FIG. 5).

Subsequently, as shown in FIG. 6B, the insulating layer 14 whose oneside is joined with the metal layer 15 is laminated onto the metal layer12. In particular, a one-side metal-coated resin prepreg isthermocompressed on the metal layer 12 (step S2 in FIG. 5), so that theinsulating layer 14 is formed on the metal layer 12, on which the metallayer 15 is formed.

Further, as shown in FIG. 6B, photoresist R is applied onto the metallayer 15 (step S3 in FIG. 5), and a predetermined resist pattern isformed by way of exposure and development processes (step S4 in FIG. 5).

Subsequently, as shown in FIG. 6C, an etching process is performed byusing a resist pattern as a mask, and a metal wiring pattern is formedon the metal layer 15 (step S5 in FIG. 5). Accordingly, the metal wiringpattern of the signal line 15 a and ground lines 15 b is formed.

As the pattern formation of the metal layer 15 is achieved and thephotoresist R is removed, the insulating layer 16 whose one side isjoined with the metal layer 17 is laminated onto the metal layer 15 asshown in FIG. 6D. In particular, the one-side metal-coated resin prepregis thermocompressed on the metal layer 15 (metal wiring pattern) (stepS6 in FIG. 5). Accordingly, the insulating layer 16 and the metal layer17 are laminated to form a strip line (signal line 15 a).

Subsequently, as shown in FIG. 6F, a grooving process is carried out byway of laser beam irradiation, an end mill process, etc., so that thegrooves are formed on both the sides of the signal line 15 a along theextended direction of the signal line 15 a, to intersect the groundlines 15 b downwardly from above and to reach a layer lower than thesignal line 15 a i.e. the metal layer 12 (step S7 in FIG. 5).

Then, as shown in FIG. 6G, the upper surfaces and the groove portions 19are subjected to a metal plating process (step S8 in FIG. 5). By meansof this metal plated layer 18, the metal layer 12 and the metal layer 17are electrically connected, and the printed wiring board with thecoaxial line structure is formed.

Subsequently, as shown in FIG. 6H, the cut-off portion 2 a is formed bycutting at a tip upper part of the printed wiring board with the coaxialline structure, whereby a predetermined area of the upper surfaces ofthe signal line 15 a and the ground lines 15 b is exposed, theconnection part connecting with the probe tip part 3 is formed, and theprobe main body 2 is completed after the whole forming processes (stepS9 in FIG. 5).

In addition, it is preferable that each of the above-mentionedinsulating layers is a prepreg including any of polyimide resin, BCBresin, polyamide resin, polyoxazole resin, epoxy resin, Teflon(registered trademark) resin, and cycloolefin resin.

Further, it is desirable that each of the above-mentioned metal layersformed of either gold, silver, or copper and the metal plated layer 18is copper plated.

Further, the method of forming the above mentioned cut-off portion 2 amay be a method disclosed in Japanese Patent Application Publication(KOKAI) No. H10-242594 and Japanese Patent Application Publication(KOKAI) No. 2001-156444, i.e., a method of manufacturing a printedwiring board in which an opening is formed in the printed board.

The method is such that a cut-off portion is provided beforehand for aprepreg layer of the printed circuit corresponding to a portion wishingto form the cut-off portion, a printed wiring board is made through theusual lamination process, and they are unified.

Hereafter, using the illustrated flow steps in FIG. 18A through FIG.28B, a particular example will be described along with the flowchart inFIG. 29. In addition, FIG. 18A, FIG. 19A, FIG. 20A, FIG. 21A, FIG. 22A,FIG. 23A, FIG. 24A, FIG. 25A, FIG. 26A, FIG. 27A, and FIG. 28A are viewsfrom the front side of the probe main body 2 to be made, and FIG. 18B,FIG. 19B, FIG. 20B, FIG. 21B, FIG. 22B, FIG. 23B, FIG. 24B, FIG. 25B,FIG. 26B, FIG. 27B, and FIG. 28B are the side views corresponding tothem.

Firstly, as shown in FIG. 18A and FIG. 18B, the double sided metal cladresin core substrate is prepared in which the thin-film metal layers 15and 12 are respectively joined with both sides of the insulating layer14 (step ST1 in FIG. 29).

Then, as shown in FIG. 19A and FIG. 19B, the photoresist R is appliedonto the metal layer 15 (step ST2 in FIG. 29), and the predeterminedresist pattern is formed by way of the exposure and developmentprocesses (step ST3 in FIG. 29).

Subsequently, as shown in FIG. 20A and FIG. 20B, an etching process isperformed by using a resist pattern as a mask, and a metal wiringpattern is formed on the metal layer 15 (step ST4 of FIG. 29).Accordingly, the metal wiring pattern is formed (hereinafter metal layer15 may be referred to as metal wiring pattern 15).

As the pattern formation of the metal layer 15 is achieved and thephotoresist R is removed, a partially cured resin layer 51 whose uppersurface is joined with the metal layer 17 is prepared (step ST5 in FIG.29) as shown in FIG. 21A and FIG. 21B, and the tip portion of thepartially cured resin layer 51 is subjected to cut-off processing (stepST6 of FIG. 29) as shown in FIG. 22A and FIG. 22B. In addition, thepartially cured resin layer 51 is made from a resin layer in a pre-curedstate, generally referred to as non-flow resin and low flow resin, andepoxy resin in the partially cured state, phenol resin, imide resin, BTresin, Teflon (registered trademark) resin, etc. are used.

As shown in FIG. 23A and FIG. 23B, the partially cured resin layer 51 isheat pressed on the metal wiring pattern 15, to thereby cure thepartially cured resin layer 51 completely (step ST7 in FIG. 29).Further, at this time, as illustrated, part of the partially cured resin51 subjected to the cut processing is hollow.

Next, as shown in FIG. 24A and FIG. 24B, the insulating layer 11 (singlesided metal clad resin prepreg) whose underside is joined with the metallayer 13 is thermocompressed from the underside of the metal layer 12for reinforcement (step ST8 in FIG. 29).

Being reinforced to be in a state as shown in FIG. 25A and FIG. 25B, thegrooving process is carried out by way of the laser beam irradiation,the end mill etc., so as to reach the metal layer 12 as shown in FIG.26A and FIG. 26B (step ST9 of FIG. 29).

As shown in FIG. 27A and FIG. 27B, the upper surfaces and the grooveportions 19 are subjected to the metal plating process (electrolesscopper plating process) (step ST10 of FIG. 29). By means of this metalplated layer 18, the metal layer 12 and the metal layer 17 areelectrically connected together, and the printed wiring board of coaxialline structure is formed.

Subsequently, as shown in FIG. 28A and FIG. 28B, a portion of thepartially cured resin layer 51 which is hollow is removed by cutting toform the cut-off portion 2 a (step ST11 of FIG. 29).

Then, according to the flowchart in FIG. 7 and the flow steps of FIG. 8Athrough FIG. 8E corresponding to the flowchart, a method of making theprobe tip part 3 (without contact bumps 7) on the substrate 5 shown inFIG. 1 by way of a lift-off method will be described.

First, as shown in FIG. 8A, by any of techniques, such as vacuumdeposition, sputtering, CVD, plating, etc., the metal layer 9 is formedon the upper surface of the substrate 5 which is made of silicon orglass (step S11 in FIG. 7), and the insulating layer 8 is further formedon the metal layer 9 (step S12 in FIG. 7).

Next, the photoresist R is applied to the insulating layer 8 (step S13in FIG. 7), and a resist pattern is formed by way of the exposure anddevelopment processes, as shown in FIG. 8D (step S14 in FIG. 7).

Subsequently, by any of the techniques, such as vacuum deposition,sputtering, CVD, plating, etc., the metal layer 10 is deposited on theinsulating layer 8 in which the resist pattern is formed as shown inFIG. 8D (step S15 in FIG. 7).

As shown in FIG. 8E, the photoresist R is removed by soaking thesubstrate in a solvent, whereby the metal layer 10 on the resist patternis removed, the metal wiring pattern of the signal electrode 10 a andthe ground electrodes 10 b is formed on the insulating layer 8, and theprobe tip part 3 is completed (step S16 in FIG. 7).

Then, according to the flowchart in FIG. 9 and the flow steps in FIG.10A through FIG. 10F corresponding to the flowchart, a meted of makingthe probe tip part 3 (without contact bumps 7) on the substrate 5 by theetching process will be described.

First, as shown in FIG. 10A, by any of the techniques, such as vacuumdeposition, sputtering, CVD, plating, etc., the metal layer 9 is formedon the upper surface of the substrate 5 which is made of silicon orglass (step S21 in FIG. 9), and the insulating layer 8 is further formedon the metal layer 9 (step S22 in FIG. 9).

Subsequently, as shown in FIG. 10C, by any of the techniques, such asvacuum deposition, sputtering, CVD, plating, etc., the metal layer 10 isformed on the insulating layer 8 (step S23 in FIG. 9).

Next, the photoresist R is applied onto the metal layer 10 (step S24 inFIG. 9), and a resist pattern is formed by way of the exposure anddevelopment processes, as shown in FIG. 10D (step S25 in FIG. 9).

As shown in FIG. 10E, the metal layer 10 is processed by using a resistpattern as a mask by way of chemistry or plasma etching, and the metalwiring pattern to be the signal electrode 10 a and the ground electrodes10 b is formed (step S26 in FIG. 9).

Finally, the photoresist R is removed by soaking the substrate in thesolvent as shown in FIG. 10F, to thereby complete the probe tip part 3(step S27 in FIG. 9).

In addition, according to the production method as described above withreference to the flowchart in FIG. 9, it is possible to provide anelectrode pitch of less than 10 μm (minimum is 2 μm).

Then, according to the flowchart in FIG. 11 and the flow steps in FIG.12A through FIG. 12D corresponding to the flowchart, a method of makingthe probe tip part 3 (without contact bumps 7) by way of the etchingprocess without using the substrate 5 will be described.

First, as shown in FIG. 12A, the double sided metal clad resin coresubstrate in which the thin-film metal layers 9 and 10 are respectivelyjoined with both sides of the insulating layer 8 is prepared (step S31in FIG. 11).

Next, the photoresist R is applied to the metal layer 10 (step S32 inFIG. 11), and a resist pattern is formed by way of the exposure anddevelopment processes as shown in FIG. 12B (step S33 of FIG. 11).

As shown in FIG. 12C, the metal layer 10 is processed by using a resistpattern as a mask by way of chemistry or plasma etching, and the metalwiring pattern to be the signal electrode 10 a and the ground electrodes10 b is formed (step S34 in FIG. 11).

Finally, by soaking the substrate in the solvent, the photoresist R isremoved as shown in FIG. 12D, to thereby complete the probe tip part(step S35 in FIG. 11).

In addition, according to the production method as described above withreference to the flowchart in FIG. 11, it is possible to provide anelectrode pitch of 10 μm (minimum).

In addition, in the method of making the probe tip part 3 as describedwith reference to FIG. 7-FIG. 12D, it is preferable that each insulatinglayer of the probe tip part 3 is a prepreg including any of polyimideresin, BCB resin, polyamide resin, polyoxazole resin, epoxy resin,Teflon (registered trademark) resin, and cycloolefin resin. Further, itis desirable that each of the above-mentioned metal layers is formed ofeither gold, silver, or copper.

Then, according to the flowchart in FIG. 13 and the flow steps in FIG.14A through FIG. 14D corresponding to the flowchart, a method of makingthe contact bumps 7 at the probe tip part 3 will be described. Inaddition, in this description, a case where the contact bumps 7 areprovided for the probe tip part 3 formed on the substrate 5 will bedescribed by way of example.

First, as shown in FIG. 14A, the probe tip part 3 (printed wiring board)is prepared which has not formed therein the contact bumps to be made byway of the process of FIG. 7 or FIG. 9 (step S41 of FIG. 13).

Subsequently, the photoresist R is applied onto the metal layer 10 (stepS42 in FIG. 13), and a resist pattern R is formed by way of exposure anddevelopment as shown in FIG. 14B (step S43 of FIG. 13).

As shown in FIG. 14C, any one of gold, silver, copper, etc., isdeposited on the resist pattern R by any of the techniques, such asvacuum deposition, sputtering, CVD, plating, etc., to form the contactlayer 7 (step S44 in FIG. 13).

Further, as shown in FIG. 14D, the photoresist R is removed by soakingthe substrate in the solvent, whereby the contact layer 7 on the resistpattern is removed, whereby the signal contact bump 7 a is formed onsignal electrode 10 a, and the grounding contact bumps 7 b are formed onthe ground electrodes 10 b (step S45 in FIG. 13).

In addition, in the case where contact durability is required, it isdesirable that a metal material for the contact bumps 7 is a metal withhigh hardness. As examples of such a metal, there may be mentionednickel, nickel alloy, W, W alloy, Pt, Pt alloy, etc. Among these, nickeland nickel alloy are desirably subjected to an Au plating process inorder to prevent surface oxidization.

As described above, according to the first preferred embodiment inaccordance with the present invention, the contact probe 100 is madefrom the printed wiring board, so that the probe tip part 3 with thefine electrode pitch (for example, less than 50 μm) can be easily formedwith sufficient accuracy.

Therefore, the probe tip 3 can be pressed against the fine pitch portionformed in the semiconductor integrated circuit, the package for thesemiconductor integrated circuit, the printed circuit board, etc., andits high speed and high frequency measurement can be realized.

Further, since the electric connection between the probe tip part 3 andthe measurement apparatus is achieved through the probe main body 2, theeasy and exact connection can be achieved. In other words, since theprobe main body 2 is made from the printed wiring board having thecoaxial line structure, it is possible to facilitate the connection withthe probe tip part 3 and the connection with the coaxial cable from themeasurement apparatus respectively. In particular, since the connectionbetween the probe tip part 3 to have the fine structure and the probemain body 2 having the coaxial line structure is connection between thesubstrates, it can be performed through the fine bumps 4, and it ispossible to realize easy and exact electric connection.

Further, the probe main body 2 has the coaxial line structure, so thattransmission efficiency of high speed and high frequency signal can beimproved, the incoming noise and the cross talk occurred between thewirings can be reduced.

In addition, in the above-mentioned first preferred embodiment, althoughthe electrode pitch between the signal contact bump 7 a and thegrounding contact bumps 7 b is set to 10-50 μm, the contact probe of thepresent invention is not limited to it. Even in the case where theelectrode pitch is arranged to be less than 10 μm or not less than 50μm, it is possible to employ the contact probe and the method of makingthe same in accordance with the present invention, and obtain theabove-mentioned operational effects.

Then, with reference to FIG. 15 through FIG. 17B, the contact probecorresponding to a plurality of channels (plurality of groups) will bedescribed as a second preferred embodiment in accordance with thepresent invention.

FIG. 15 is a plan view showing the second preferred embodiment of thecontact probe in accordance with the present invention. FIG. 16A is aplan view showing a structure of the probe main body of the contactprobe of FIG. 15, and FIG. 16B is a front view (along arrows A-A).Further, FIG. 17A is a plan view showing a structure of the probe tippart of the contact probe of FIG. 15, and FIG. 17B is a front view(along arrows B-B).

In addition, since the contact probe as shown in the second preferredembodiment can be made in a similar manner to the production method asshown in the above-mentioned first preferred embodiment, the detailedexplanation of the production method will not be repeated. Further, likereference signs are used to refer to like parts, and the detaileddescription of them will not be repeated.

The contact probe 101 as shown in FIG. 15 is arranged such that theprobe main body 20 and the probe tip part 30 are mutually joined bythermocompression using the fine bumps (not shown). The contact probe101 as shown in FIG. 15 is arranged to cope with a plurality of channelsignals (eight-channel is shown in figure by way of example), and it ispossible to connect the tip of the coaxial cable 40 from the measurementapparatus (not shown) to the rear end of the probe main body 20.

As shown, the probe main body 20 is formed in the shape of a fan where awidth at the tip is narrow and a width at the rear end is wide, and apitch between adjoining coaxial cables is widened, so that a pluralityof coaxial cables 40 can easily be connected together side-by-side.

Further, as shown in FIG. 16A and FIG. 16B, as for the probe main body20, the cut-off portion 20 a is formed at the tip part, and the rear endof the probe tip part 30 is connected to this cut-off portion 20 a.Arranged side-by-side at a predetermined pitch in the cut-off portion 20a are tips of a plurality of coaxial lines 20 b respectively connectedto the corresponding coaxial cables 40. An upper surface of each of thesignal line 15 a and ground lines 15 b is exposed.

On the other hand, as shown in FIG. 17A and FIG. 17B, like the probemain body 20, the probe tip part 30 is formed in the shape of a fanwhere a width at the tip is narrow and a width at the rear end is wide,and a pitch between adjoining signal electrodes 10 a at the rear end isarranged to be the same as that of the signal lines 15 a exposedside-by-side at the cut-off portion 20 a of the probe main body 20.

Further, as for the tip of the probe tip part 30 used as a contact partwith respect to the measuring object, a plurality of channels of signalelectrodes 10 a and ground electrodes 10 b are arranged side-by-side. Inaddition, the pitch between the signal electrode 10 a and groundelectrode 10 b which adjoin each other at the probe tip, and the pitchbetween the signal electrodes 10 a are each arranged to have apredetermined value of 10-50 μm, for example.

Thus, as described in the first preferred embodiment, since the probetip part 30 coping with the plurality of channels is produced by aprinted wiring board formation technology, it is possible to form andarrange a plurality of contact electrodes at a desired pitch easily,even if the pitch between the adjacent electrodes is a fine pitch ofless than 50 μm, for example.

As described above, according to the second preferred embodiment inaccordance with the present invention, by making the probe tip part 30with the printed wiring board, it is possible to form and arrange theplurality of channels of electrodes at the contact probe tip, in whichthe electrode pitch is fine (for example, less than 50 μm). Therefore,even in the case where the plurality of channels of measuring objectsare located at a fine pitch, it is possible to measure the high speedand high frequency signal for each channel by the contact probe 101which copes with the plurality of channels.

Further, by forming the shape of the probe main body 2 in the shape of afan where the width of the rear end is wide, it is possible to widen thepitch between the adjoining channels at the rear end, and to easilyachieve the connection with the coaxial cable which is from themeasurement apparatus.

In addition, in the above-mentioned second preferred embodiment,although the pitch between the signal electrode 10 a and groundelectrode 10 b and the pitch between the signal electrodes 10 a are eachset to 10-50 μm (for example), the contact probe of the presentinvention is not limited to it. In other words, according to the methodof making the contact probe in accordance with the present invention,even in the case where the electrode pitches are each arranged to beless than 10 μm or not less than 50 μm (for example), a multi-channelcontact probe (such as eight channels and 16 channels) which isdifficult for the conventional production method to realize can beobtained easily, and it is possible to obtain the above-mentionedoperational effects.

Further, in the case where a substrate 54 in which a plurality ofcoaxial lines 55 as shown in FIG. 30A are formed in parallel is producedand the coaxial lines 55 are connected to the coaxial cables by way ofthe method as shown in the above-mentioned preferred embodiment, it ispossible to:

firstly, form a cut-off portion 55 a so that signal lines 56 and groundelectrodes 57 may be exposed upwards at portions connected the coaxialcables, i.e., tip portions of the respective coaxial lines 55 in thesubstrate 54, as shown in FIG. 30B; and

while, form a cut-off portion 60 a so that signal lines 61 and groundelectrodes 62 may be exposed to upper surfaces at portions connected tothe coaxial lines 55 in coaxial cables 60, i.e., tip portions of thecoaxial cables 60, as shown in FIG. 30C.

As shown in FIG. 31A, the cut-off portion 55 a of the coaxial line 55 inthe substrate 54 and the cut-off portion 60 a of the coaxial cable 60are caused to face each other and further joined together in a situationwhere the respective signal lines and ground electrodes are inelectrical contact with each other as shown in FIG. 31B.

In addition, joining the coaxial line 55 with the coaxial cable 60 isrealized such that both the metal portion of the coaxial line 55 and themetal portion of the coaxial cable 60 to be joined together are preparedfor soldering in advance, and the joining portions are brought intocontact with each other, and then generally heated.

According to such a joining method, since the connection in which thecoaxial structure is substantially maintained is available, it ispossible to reduce the degradation of the transmission characteristic ofthe connection part.

Further, by the above-mentioned joining method, as shown in FIG. 31C, itis possible to connect the plurality of coaxial cables 60 with theplurality of coaxial lines 55.

INDUSTRIAL APPLICABILITY

The contact probe in accordance with the present invention can be usedfor measuring and evaluating the high speed and high frequencycharacteristic in the semiconductor integrated circuit, the package forthe semiconductor integrated circuit, the printed circuit board, etc.

1. A contact probe used for measuring and evaluating a high speed andhigh frequency characteristic, comprising: a first printed wiring boardhaving a signal electrode and a ground electrode used as a contact partwith respect to a measuring object, in which said signal electrode andground electrode are formed of a metal wiring pattern on a substrate,and a second printed wiring board with a coaxial line structure having ashield electrode which encloses a signal line and the surroundings ofsaid signal line through an insulating layer, characterized by beingarranged such that the signal electrode of said first printed wiringboard and the signal line of said second printed wiring board areelectrically connected together, and the ground electrode of said firstprinted wiring board and the shield electrode of said second printedwiring board are electrically connected together.
 2. The contact probeas claimed in claim 1, said second printed wiring board beingcharacterized in that a ground line electrically connected to saidshield electrode is formed in the same plane as said signal line, and acut-off portion is formed so that a predetermined area of either upperor lower sides of said signal line and said ground line may be exposed,said signal line exposed at said cut-off portion is electricallyconnected to the signal electrode of said first printed wiring board,and said ground line exposed at said cut-off portion is electricallyconnected to the ground electrode of said first printed wiring board. 3.The contact probe as claimed in claim 1, characterized in that anelectrode pitch between said signal electrode and said ground electrodeis arranged to be equal to or greater than 10 μm or less than 50 μm. 4.The contact probe as claimed in claim 1, characterized in that aplurality of groups of signal electrodes and ground electrodes areformed in said first printed wiring board and corresponding groups ofsignal lines and shield electrodes are formed in said second printedwiring board, the signal electrodes of said first printed wiring boardand the signal lines of said second printed wiring board areelectrically connected together for each corresponding group, and theground electrodes of said first printed wiring board and the shieldelectrodes of said second printed wiring board are electricallyconnected together for each corresponding group.